A recent headline from the Los Angeles Times, “Teens plotting attacks tend to tip their hand,” highlights a particularly difficult grammar problem.
Do plural teens really share a singular hand? No. But would it be better to make “hand” plural, giving us “Teens plotting attacks tend to tip their hands”? Not necessarily. In fact, the consensus seems to be that, no, a plural object in a sentence like this is not an improvement over a singular subject.
This issue falls under the umbrella of what are called “agreement problems.” But unlike better-known agreement issues, notably subject-verb agreement, what’s sometimes called subject-object agreement isn’t as well known — quite possibly because it’s futile to even think about.